Calibrating tool



Nov. 21, 1944. N. MARS f GALIBRATING Tool.

Filed Jan. 7, 1944 -Q jid J5 o e 13 0 0 52 i 14 o Q 0 1 ;,g 2

j! 7 51 [l v G 55 f i' .ff f\/\/\/\/\/\/\/\ if l ummm" m m Le J7 o/ s@ m m 23 2Mb INVENTOR wlTNsssEs:

m. w' Y M-TTCSRNEY plied .tofthey strap stretched.

Patented Nov. 21, 1944 .UNITED STAT as* PATE NT N OFFICE v AIBRATINGTOL Nick Mars, Sharon, Pa., assigner to Vtestinghousev Electric & Manufacturing '(ompany, East Pittsburgh, Paf., a corporation of Pennsylvania lmunicationiJanuary 7, 1944,js,eria1No. 517,343" f` eclaims; (o1. frs- 141i My invention relates to ka calibrating toolv 'fori ,g

measuring'theV pressure developed by a pressuredevelo'ping device or tool for applying `an increasingpressure to a predetermined value on a:

' workpiece operatedby the pressure-developing toolzbeing calibrated. My invention is applicable toA Calibrating lthe setting of a strap-stretching.-device of the character in which anincreasing'f pressure 'is appliedv by the device until the pressure is increased to a predeterminedvalue, at'."which value rthe r.strap-stretching device `is automatically locked against further operationv to prevent further increase.r in the tension ap- Such a strapstretching `device is disclosedl and claimed in my n copending application, Serial No. 490,442,101I m-` provement inV strap-stretching: device, filed June; Y 11,1943,vv andassigned tothe same assignee. as

thisapplication. f vIxrthe strap-stretching device,.- of .myl copending;

application'. a hand-operated. strap-stretching, Y

. ble, for employment for stretching a metal strapA about an article and is providedfwithmeans for locking,the'strap-stretching tool against further' operation uponl the applicationY of a predetermined. force upon the strap being stretched;

Other objects and advantages Aof my invention will. beA apparent from fthe-.following description toolisemployedfor stretchingor tightening steelt.

straps kor bands .about asubstantially solidfmass: of4 material, vsuch `as lthe Acore .structures .of electricaltransformers wherel it. isl desirable toy apply the band under a. predetermined tensioni and to `maintain a predetermined constant tensioni on. the band about the` coreparts.. The-strapstretching. device causes tension. to be` applied to the tw-o ends of the strapfwrapped about, the., iron corev and asv .they tool is operated,A the*v tension. of

'y the strap' is .increased to; a predetermined'-value,v

atlv which` value the strapestretching device* releasesl a locking mechanism for .lockingthe` tool against furthenoperati'on, thusholdingthestrapunder a. predetermined tension until it is fastened,

f in. .its vdesired position: atr the desired; tension.

In. arderr to provide.. for releasing. the:V locking;

mechanismof. the strap-stretching device at the desired predetermined tension. on the metal .on

steel. band. being stretched, the?CalibratingA tool ofthe present invention is employed.. The pair ofy movable heads onsthe strap-stretchingdevice which engage .and cause the relatives-movement44 oi' theoppositerends ofthe strap being` stretched strap-stretching device operatesv andv the pressure.. at -which this, device-operates i's-indicated; thus.-

allowing for adjustments inthe mechanism coni trolling'the pressure at which the locking mechanism will' release and permitting 'its`V ready .adjustment to the desirerlvalue.A

"It 'is` anf-obje'ctof .this invention! to.v provide: a,

ofva preferred embodiment of thelinventiomreferencebeing had to the accompanying-drawing,

in whichz. l j i L Figure l is a perspective View of the calibrating tool of the inventionfillustrated as usedior calibrating a strap-stretchngy device :correspondingto that illustrated;and-describedin my aboveidentified:V copendingy application;

.l -Figuzpis averne@ Sectio-nai lview er the can A disassembled;

brating tool; i,

- Figs. 3 Iandgifare vertical andfhorizonta-l'sectional views;` respectively, .throughl a `shock-Labsorbing-pressure cylinderycomprising ay part of ,Eig.. 5 in an'enlarged 'detailedksectionalviiew ofr a check-valve controllingran air passage to and from lthepressure cylinder;

Fig.y 6-is a yView of.N parts vof vthe to'ol partially Fig.- 7 isa plan view of the basey and guide cylinder, mountedlthereon with other rparts of the Calibrating tool removed.'v

Referringto the drawing, r theA .Calibratingtool comprises@ base I- shown. as includingv a pai-r of channel'members Zand: 3` upon one end of.Y which a lguide-zand Calibrating Imemberxd vismountedf here .illustrated inthe ,form of acylinderl havv are placed between relatively .movable.abutments'` in thefcalibratingtool of this.v invention and are operatedauntl the locking 'mechanismoi thev ing a. closed-endl and adapted-'to receive and yguide ay calibrating sleeve vli extendiiflgv from a movable abutment 1 that-isf arrangedto slidealongzthe base` of the Calibrating.v tool. A mam orzcalibratingspring Hk is' provided within the Calibrating; sleeve, Sand the lcalibrating; cylinder 4, one end vof which engagesagainstl a, centering member VI2I adjacentthe clo'sedend: 5v of the calibratingcylinderfll and. theJv opposite end'of which :engages against; one wall ofthe movable-A abutmentlg.

A iixed abutment I3 is also provided, fixedly mounted as by screws I4 to the base member I at the end thereof opposite the Calibrating cylinder 4. A bore I5 is provided in the base of the abutment member I3, the walls of which, together with a piston I6, provide a closed air chamber between the piston I6 and the closed end I1 of the cylindrical bore I5, thus forming a pressure cylinder for a purpose to be later described. A guide rod I8 is provided, one end of which is attached to the piston I6 and the other end I9 of which is attached to the movable abutment 1, the rod I8 and piston I6 acting as a guide member for the movable abutment 1. The rod I8 extends through an opening in a plate or Washer 2| illustrated as attached by screws 22 to the open end of the bore I5 in the fixed abutment member I3. A spacing spring 23 is shown about the guide rod I8 between the movable abutment member 1 and the plate 2| to limit the movement of the abutment 1 toward the right, as viewed in the drawing, thus spacing the two abutments I and I3 a predetermined minimum distance apart. A check valvedevice 3| is provided for controlling the communication between the chamber formed within the bore I5 and the outside atmosphere and as best shown in Fig. 5, comprises a bore 32 through the wall 33 of the abutment member forming the chamber and including a plug 34 at the inner end of the bore and a plug 35 at the outer end of the bore. An opening 3S is provided in the plug 34 communicating from the bore 32 with the outside atmosphere andan opening 31 having a conical valve seat 38 at its inner end is provided in the plug 35. A ball valve 39 is shown against the valve seat 38 that is normally held against its seat by the spring member 4I, one end of which engages the ball valve 39 and the other end of which engages the plug 34.

Referring particularly to Fig. 1, a strapstretching tool 53 is illustrated, having a pair of relatively movable heads 54 and 55 that are actuated by repeated relative movement of the handles 5S and 51 grasped between the palm and ngers of the hand and operated to eiect, through the mechanism of the device 53, movement of the heads 54 and 55 away from each other.' In the normal Operation of the device for stretching a strap about an article, the two ends of the strap are engaged by the heads 54 and 55,

the ends of the strap overlapping so as to draw them tight. Spring mechanism is provided'in the the two heads 54 and 55 are moved in a direc-v tion away from each other in the normal operation of the device, the pressure required to move them increases until at some predetermined value locking mechanism 58 will trip and lock the tool against further operation.

In the calibrating operation, the two heads 54 and 55 of the strap-stretching device 53 are placed between the` surfaces 5I and 52 of the abutments 1 and I3 of the Calibrating device, 'as

shown in Figs. 1 and 2, and the strap-stretching device is operated in the usual manner by repeated gripping of the handles 56 and 51 between the palm and iingers of the hand thus causing the heads 54 and 55 of the tool to move away `from each other. During this operation, the main or Calibrating spring II is being compressed by movement of the abutment member 1 toward the left as viewed in the drawing until sufficient pressure is applied to cause the locking mechanism 58 of the tool 53 to trip. The value at which this tripping takes place is readable on the markings provided on the outer surface of the sleeve vI5 as it enters the Calibrating cylinder 4, thus indicating the setting of the tool being calibrated, that is, at `what value of pressure the locking mechanism will trip. If this value oi pressure is too high or too low, the mechanism contained in the handle of the strap-stretching tool 53 may be adjusted to correct for the proper value.

When the above-described operation is com-- pleted and the mechanism within the tool 53 holding the two heads 54 and 55 in their relatively separated positions is released thus permitting the head 54 to move toward the right, as shown in the drawing, the spring II will cause the abutment 1 to Ialso travel toward the right. In order to prevent back hammering or sudden violent movement of the abutment 1 under the force of the spring II, the piston I6 is provided which tends to compress the air contained within the bore I5 'between the piston I6 and the end II of the abutment member, the check valve 3I retaining the air within the chamber, except as it gradually leaks past the piston I6, and preventing its passing therefrom while permitting free ow of air from the Outside atmosphere into the chamberwithin the bore i5 when the piston I3 is moved toward the left, as shown in the drawing. The rod I8 also acts as a guide assisting 'the sleeve 6 in guiding the movable abutment member 1 in a straghtline path along the upper surface of the base member of the tube.

It will be apparent to those skilled in the arti that modifications may be made in the structure illustrated and described within the sco-pe of my invention and I do not wish to be limited otherwise than by the scope of the appended claims.

I claim as my invention:

1. The combination in a ,Calibrating tool, of a pair of spaced apart relatively movable abutment members arranged to receive between opposed surfaces thereon a pair of relatively movable heads of a strap-stretching tool for applying an increasing pressure on a strap upon movement of the heads of the tool away from each other,.an elongated base upon which said pair of abutment members are mounted, one of the abutment members being Xedly mounted at one end of the base and the other being mounted for movement on a track provided on the b`ase, a Calibrating sleeve Yextending from the movable abutment member in a direction away from the fixed abutment member andV a guide cylinder xedly attached to the other end of the base for receiving said sleeve and having means responsive to the relative movement of the cooperating sleeve and cylinder and responsive to the relative movement thereof for indiescasez'. eating' the pressure-sappliedwbetween the f-abut.

ment members by1 the strap-stretching tool being calibrated, a guide rod .extending from the; mov

ableabutmentmember through` a bore :in :the xednalbutmenttmemberfor assisting in. guiding' the: movable. abutmentzzmember', .andi a, spacing.,

tivesmovement'thereof for* indicating the; pres.

spring :about the guidefrod between thegtvzo.v

f abutmentlmembers.. o y 2. -The'rcombination a" calibrating tool, of a: pair.; of vspaced apart i relatively# movable:` abutmenty members arranged to;receive betweeniop.

l posedcsnrfacesnthereon a` pair. of relatively `mov-A able-headset, ai pressure-developing tool' for:A a'p-A Dlying'an'increasng pressure on a yworkpiece upf movement of the*v heads away vfrom eachl other, -abaseupon which said pair 4of Vabutmentm'embers. arepmound, @one-of the abutment members being fixedlylattachedtosaid base andv thezo'ther: .being mounted for movement on a trackz provided on the base, ja; calibratingsleeve member .extending from .the movable abutment member anda guidemember xedly .attached to saidgbase for receiving said sleeve, a Calibrating spring within the z sleeve and. guide membersfor increasingv .the pressure on themovableabutfment member necessary to moveritin a direction Y fromthenxedabutment member', and indicating means responsive to the relative movement of thecooperatin'gsleeve and guide means responsive to the relative movement of the sleeve and guide member for indicating the pressure applied between the abutment members by the pressure developing 'tool being calibrated, the xed abutment member having a relatively largeA lbore therein forming the walls of a chamber in chamber between the piston and the Closed end of the cylindrical bore and for checking the Iiow of air `fromsaid chamber.

3. The combination iny a caubranng i001, off'r a pair of spaced apart relatively movable abutposed surfaces thereon a pair of relatively movable heads of a strap-stretching tool for apply- 'ing an increasing pressure on a strap upon movement of the heads of the `tool away from each other, an elongated base upon which said pair of 'abutment members are mounted,one of the abutment members being xedly mounted at one end of the base and the other being mounted for movement on a track provided on the base, ar

Calibrating sleeve extending from the movable abutment member in a direction away from the xed abutment member and a guide cylinder xedly attached to the other end of the base for sure applied between 1 the: abutment members byl they vstrapstretching l tool being calibrated, the

fixed f abutment member having' a..-relativelyr largey L bore thereinrformingthe walls of aV chamber in alignment'rwith Vthe axisuof movement-:of the movableabutment member. andclosed atthe end remote :rromthe` movable member, --ar;piston within said borer the inner end of which forms onezwallof the Chamber, and a pistonrod Cone meeting ,said piston. to said movable 'abutment member and movablewithsaid movable abutmentmemberfa spacing springbetween said.

movable abutment member. and said fixed abut;-

.' ment member, andl a checkvvalve for permitting free :How of .air from the youtside atmosphere to the chamber between the piston and the closedend .of-the Cylindricalbore and for Checkingthe flowof air from saidl chamber.l y y, 4.. The combinationin a Calibrating tool, lof -a pair of` spaced. apart relatively movable. abutment from the fixed abutment member and a guidev members arranged to r.receive between opposedy surfacesv thereon a `pair 'of relatively movable yheads of a strap-stretching tool for applying an increasing pressure ona strap upon movementof theheads of the-.tooltaway from eachother,

elongated'base -uponwhich said pair of abutment members are mounted, oneof the abutmentmem.- bersbeing xedly mounted at one end ofthe base and the other being mounted yfor movement on the base, a Calibrating member extending from the movable abutment member in a direction away f member xedly attached to the other end of the yment members arranged to receive between'opreceiving said sleeve and having a closed end, a

calibrating spring within the sleeve and guide cylinder having one end engaging the closed end ofthe cylinder and the `other end engaging the `movable abutment member for increasing thepressure on the movable abutment upon movement thereof in a direction from the xed abutment member, indicating means responsive to the relative movement of the cooperating sleeve and cylinder and responsive to the relabase for receiving said Calibrating member, a Calibrating spring having one end engaging the guide member and the other end engaging the movable abutment member for increasing the pressure onthemovable abutment member necessary to ymove it in a direction from the fixed abutment member, indicating means responsive to the relative movement of the cooperating Calibrating and guide members andresponsive to the relative movement thereof for indicating the pressure applied between the abutment members by the strap-stretching tool being calibrated, a guide rod extending from the movable abutment member through a bore in the fixed abutment member for assisting in guiding' the movable abutment member, and a spacing spring about the guide rodV between the two abutment members.

5. The combination in a- Calibrating tool, of a pairoi spaced apart relatively movable abutment members arranged to receive between opposedsurfaces thereon a pair of relatively movable heads of a pressure developing tool for applying an increasing pressure'on a workpiece upon movement of the heads away from each other, a base upon which said pair of abutment members are mounted, one of the abutment members being rlxedly rattached to said base and the other being mounted for movement on the base, a Calibrating member extending from the movable abutment member and a guide member xedly attached to said base for receiving said Calibrating member, a Calibra-ting spring for biasing the Calibrating member and guidev member and for increasing thev pressure required on the movable abutment r member to move it in a direction away from the xed abutment member, and indicatingv means responsive to the relative movement of the cooperating Calibrating member and guide member '4 responsive to the relative movement of the ycalibrating member and guide lmember for indicating the pressure applied between the abutment members by the pressure developing tool being calibrated, the fixed abutment member having a relatively large bore therein ormingthe walls of a chamber in alignment with the axis of movement of the movable abutment .member and closed at the end remote from the movable member, a piston within said bore, and a piston rod connecting said piston to said movable abutment member and movable with said movable abutment member, and a check valve for permitting free flow of air from the outside atmosphere to the chamber between the piston and the closed end of the cylindrical bore and for checking the flow of air from said chamber.

6. The combination in a calibrating tool, of a pair of spaced apart relatively movable abutment members arranged to receive betvveenv opposed surfaces thereon a pair of relatively movable heads of a strap-stretching tool for applying an increasing pressure on a strap upon movement of the heads of the tool away from each other, an elongated base upon which said pair of abutment members are mounted, one of the abutment members being xedly mounted at one end of the base and the other being mounted for movement on the base, a Calibrating member extending from the movable abutment member in a direction away from the fixed abutment member and a guide member xedly attached to the base and having a bore for receiving said calibrating meinber and having a closed end, the Calibrating member also having a bore in alignment with the base in theguide member, a calibrating spring having one end within the bore in the' calibrating member and the other end within the bore in the guide member for biasing the movable abutment member toward the Xed abutment member and for increasing the pressure on the movable abutment member necessary to move it in a direction fromthe iixed abutment member as its.

movement from the iixed abutment member increases, indicating means responsive to the relative movement of the cooperating Calibrating` member and guide member and responsive tothe relative movement thereof for indicating the pressure applied between the abutment members by the strap-stretching toolbeing calibrated, the fixed abutment member havingl a relatively large 3 bore therein formin'gthe walls of a chamber in member and movable with said movable abutment member.

' l NCK MARS. 

